Figure 5.

Effect of RXR ligands on the transcriptional activity VgEcR/RXR complex. (A) Dose–response for ponA, an RXR ligand, or ponA plus a constant concentration of RXR ligand (100 nM). Increasing concentrations of the RXR ligand LG268 had no effect on the VgEcR/RXR heterodimer. Combination of 100 nM LG268 with increasing amounts of ponA resulted in considerably greater inductions than when ponA was used alone. (B) Combined effect of ecdysteroids and RXR ligands on VgEcR/RXR activation. Cells were treated with 10 μM murA, ponA, or inokosterone, alone or in combination with one of three RXR ligands present at 100 nM concentration. (C) LG268 potentiates the inducing properties of nonsteroidal VgEcR agonists. Cells were treated with 10 μM nonsteroidal ecdysone receptor ligand, alone or in combination with LG268 at 100 nM concentration. These mixtures induced higher levels of reporter activity than 10 μM murA.